THE DEVELOPMENT OF NB3SN SUPERCONDUCTOR WITH MICRON SIZE FILAMENTS, HIGH CURRENT DENSITIES AND LOW MAGNITIZATION

MAGNETIC FUSION REQUIRES THE DEVELOPMENT OF LOW COST, HIGH FIELD SUPERCONDUCTORS SUCH AS NIOBIUM TIN FORUSE IN THE POLOIDAL AND TOROIDAL FIELD COILS. THE POLOIDAL SUPERCONDUCTOR IS REQUIRED TO HAVE LOW ELECTRICAL LOSS DURING THE OHMIC HEATING PULSES. THE "INTERNAL TIN" PROCESSFOR NIOBIUM TIN PROMISES TO BE THE LOW COST METHOD OF MANUFACTURE FOR FUTURE LARGE MAGNET REQUIREMENTS IN FUSHION AND HIGH ENERGY PHYSICS. LOW LOSS PULSED FUSION MAGNETS REQUIRE SUPERCONDUCTOR WITH FILAMENTS IN THE MICRON RANGE THAT ARE WEAKLY IF NOT COMPLETELY UNCOUPLED. TO MAXIMIZE THE CURRENT DENSITY IN THE "INTERNAL TIN" PROCESS AND HENCE REDUCE COST PER AMPERE METER FOR THE SUPERCONDUCTOR REQUIRESMATRIX TO NIOBIUM RATIOS SMALLER THAN 3 TO 1. FILAMENT SPACING AT THESE RATIOS BECOME EXTREMELY SMALL. THEREFORE FILAMENT SHAPE, UNIFORMITY, AND SPACING MUST BE MAINTAINED TO MINIMIZE FILAMENT BRIDGING DURING REACTION. THE PROPOSEDWORK FOCUSES ON INVESTIGATING THE EFFECT OF BILLET DESIGNS, THERMOMECHANICAL PROCESSING PARAMETERS, AND STRENGTH RATIOS OF THE MATRIX AND NIOBIUM ON THE SYMMETRY AND UNIFORMITY OF THE FILAMENTS. IMPROVEMENTS WILL ALLOW SUBSTANTIAL INCREASES IN CURRENT DENSITY AND THE ELIMINATION OF FILAMENTBRIDGING. THE RESULTING CONDUCTORS WILL ALSO BE MORE SUITABLE FOR APPLICATIONS SUCH AS; PULSED FIELDS, A.C. MOTORS AND GENERATORS, AND HIGH ENERGY PHYSICS MAGNETS.